In the recent information and electronic industry, inorganic substances such as silicon oxides or silicon nitrides have been frequently used. However, the demand for novel materials having high performance is growing in accordance with the increased requirement for small-sized devices having high efficiency. An interest in polymer that has low dielectric constant and water absorption, excellent metal adhesion, mechanical strength, thermal stability, and transparency, and high glass transition temperature (Tg>250° C.) as a material capable of satisfying the high-performance properties is growing.
The polymer may be used as electronic materials such as insulating films of semiconductors or TFT-LCDs, films for protecting polarizing plates, multichip modules, integrated circuits, printed circuit boards, sealing materials for electronic devices, or flat panel displays.
The cyclic olefin polymer is a polymer of cyclic monomers such as norbornene, and has better transparency, heat resistance, and resistance to chemicals, and very low birefringence and water absorption as compared to a known olefin polymer. Therefore, the cyclic olefin polymer may be used as optical materials such as CD, DVD, and POFs (Plastic Optical Fibers), information electronic materials such as capacitor films and low dielectric materials, and medical materials such as syringes having the low absorption property and blister packaging.
Examples of a polymerization method of the cyclic olefin may include ROMP (Ring Opening Metathesis Polymerization), copolymerization in conjunction with ethylene, and addition polymerization shown in the following Reaction scheme 1. In the above-mentioned polymerization methods, transition metal catalysts such as metallocene compounds and Ni or Pd-compounds are used. Characteristics of the polymerization reaction and polymers to be produced depend on the central metal, the ligand, and the composition of the catalyst.

In respects to the catalyst used in the ROMP, chlorides such as TiCl4 and WCl6 or carbonyl organic metal compounds are reacted with Lewis acid cocatalysts such as R3Al and Et2AlCl to form metal carbene or metallocyclobutane catalyst active species. The active species are reacted with double bonds of olefins to be ring-opened via a ring intermediate of metallocyclobutane, thereby forming a final product having a double bond (Ivin, K. J.; O'Donnel, J. H.; Rooney, J. J.; Steward, C. D. Makromol. Chem. 1979, Vol. 180, 1975). Since the polymer that is produced by using the ROMP has one double bond per a repeating unit of monomer, thermal stability and oxidation stability are significantly reduced. Thus, the polymer is frequently used as a thermosetting resin.
The first copolymer of ethylene and norbornene was produced by using a titanium-based Ziegler-Natta catalyst manufactured by Leuna, Co., but is disadvantageous in that the produced copolymer is not transparent due to residual impurity and Tg is limited within a range of 140° C. or less (Koinzer, P. et al., German Pat. No. 109,224).
With respect to the addition polymerization method of the cyclic olefin monomers, Gaylord, N. G. et al. suggested a method of polymerizing norbornene by using a [Pd(C6H5CN)Cl2]2 catalyst (Gaylord, N. G.; Deshpande, A. B.; Mandal, B. M.; Martan, M. J. Macromol. Sci. -Chem. 1977, Vol. A11(5), 1053 - 1070). Polynorbornene that is produced by using a zirconium-based metallocene catalyst has very high crystallinity, is not dissolved in a typical organic solvent, has no glass transition temperature, and is thermally decomposed (Kaminsky, W.; Bark, A.; Drake, I. Stud. Surf. Catal. 1990, Vol. 56, 425). On the other hand, polynorbornene that is produced by using a Pd-metal catalyst is dissolved in an organic solvent such as tetrachloroethylene, chlorobenzene, or dichlorobenzene, and has a molecular weight of 100,000 or more and Tg of 300° C. or higher.
However, in order to use polymers as information and electronic materials, predetermined adhesion strength is required to a surface of metal such as silicon, silicon oxides, silicon nitrides, alumina, copper, aluminum, gold, silver, platinum, titanium, nickel, tantalum, and chromium. Accordingly, in the case of the norbornene polymer, efforts have been made to provide a polar functional group to a norbornene monomer in order to control metal adhesion and various electric, optical, chemical, and physical properties.
U.S. Pat. No. 3,330,815 discloses a method of polymerizing norbornene monomers having polar functional groups by using (PhCN)2PdCl2 dimers and the like as a catalyst. However, the method is problematic in that since the catalyst species are deactivated due to the polar functional groups of the monomers to disturb a polymerization reaction, it is difficult to obtain a polymer having a molecular weight of 10,000 or more.
U.S. Pat. No. 5,705,503 discloses a method of polymerizing norbornene monomers having polar functional groups by using ((Allyl)PdCl)2/AgSbF6 as a catalyst composite. However, in the method, a ratio of the catalyst to the monomers is 1:100 to 1:250, which means that the catalyst is used in an excessive amount. Accordingly, since the large amount of catalyst residue remains in the final polymer, there are possibilities of deterioration of the polymer resulting from thermal oxidation and reduction in light transmission.
In the case of when ester norbornene monomers are polymerized by using a cation type [Pd(CH3CN)4][BF4]2 catalyst, the polymerization yield is low and exo isomers are selectively polymerized (Sen, A.; Lai, T. W. J. Am. Chem. Soc. 1981, Vol. 103, 4627-4629). In the case of when norbornene having an ester group or an acetyl group is polymerized, since the catalyst needs to be used in an excessive amount so that a ratio of the catalyst to monomers is about 1/100 to 1/400, it is difficult to remove the catalyst residue after the polymerization.
U.S. Pat. No. 6,455,650 discloses a method of polymerizing norbornene monomers having functional groups by using [(R′)zM(L′)x(L″)y]b[WCA]d as a catalyst composite. However, the method is problematic in that since the yield is 5% which is considered to be very low in the case of when the norbornene monomers having the functional groups are polymerized, it is difficult for the catalyst composite to be used to produce the polymer having the polar functional groups.
The document which has been made by Lipian et al. (Sen, et al., Organometallics 2001, Vol. 20, 2802-2812) discloses that in a polymerization reaction of ester norbornene by activating [(1,5-cyclooctadiene) (CH3)Pd(Cl)] by means of an organic phosphorus system such as PPh3 and a cocatalyst such as [Na]+[B(3,5-(CF3)2C6H3)4]−, an excessive amount of catalyst is used so that a ratio of the catalyst to monomers is about 1/400 to produce a polymer having a molecular weight of about 6,500 at a polymerization yield of 40% or less.
Meanwhile, a catalyst system that is used in the above-mentioned polymerization methods typically includes a main catalyst which is a metal complex and a cocatalyst which is an ionic compound.
A homogeneous Ziegler-Natta catalyst system that is a catalyst having multi-active sites used in a known polymerization process includes methyl aluminoxane (MAO) as a cocatalyst to improve reactivity of the catalyst. However, the catalyst system is problematic in that since it should be used in an excessive amount in respects to a catalyst precursor, economic efficiency is poor and undesirable postprocess should be performed.
After a metallocene catalyst having a single active site was developed, in order to avoid the above-mentioned problems, perfluoroarylborate type of noncoordination anions that are capable of providing a single cation active species to a catalyst precursor, has electric charges that are as low as −1 or −2, and are used to desirably perform delocalization of the electric charges have been used as a cocatalyst (Chem. Rev. 1988, Vol. 88, 1405-1421; Chem. Rev. 1993, Vol. 93, 927-942).
The anions are used in a salt form along with trityl cations that are used to perform a removal reaction of alkide or hydride or dialkylammonium cations that are used to perform protonolysis. Representative examples of the borate cocatalyst compound may include [Ph3C][B(C6F5)4] and [PhNMe2H][B(C6F5)4].
During the polymerization reaction, the cation portions of the cocatalyst are reacted with leaving groups of the metal precursor to provide cationic properties to the metal precursor and form ion pairs along with anion portions of the cocatalyst. In this connection, the anions are slightly coordinated with the metal and easily exchanged with olefin monomers, causing a polymerization reaction.
However, since the ion pairs substantially act as the catalyst active species but are thermally and chemically unstable, the ion pairs are sensitively reacted with solvents and monomers to reduce reactivity of the catalyst. Particularly, in the case of the cocatalyst compound containing nitrogen, a neutral amine compound is generated during an activation reaction of the catalyst, and the amine compound is capable of strongly interacting with a cation type organic metal catalyst, causing reduction in activity of polymerization. In order to avoid this, the use of carbenium, oxonium, and sulfonium cations instead of ammonium cations is known in the art (EP No. 0426,637).
Meanwhile, in the case of when cyclic olefin monomers are polymerized by using MAO or organic aluminum as a cocatalyst, high polymerization activity is ensured during polymerization of nonpolar norbornene such as norbornene, alkylnorbornene, and silylnorbornene. However, the very low polymerization activity is ensured in respects to polar norbornene such as ester or acetyl norbornene (U.S. Pat. Nos. 5,468,819, 5,569,730, 5,912,313, 6,031,058, and 6,455,650).
That is, in the case of catalyst system for polymerizing cyclic olefins having the polar functional group, the catalyst system is produced by using various types of cocatalysts. However, since the catalyst is sensitively reacted with monomers to be deactivated due to the polar functional group or to have reduced thermal stability, it is difficult for the catalyst system to be used in high temperature polymerization. Accordingly, in the case of typical olefins having the polar functional group, it is impossible to obtain the polymerization yield, the molecular weight of the polymer to be produced, and the amount of the catalyst that satisfy all the requirements. In addition, in the case of when the catalyst is used in an excessive amount, there are problems in that the obtained polymer is colored and transparency is poor.
Accordingly, there is a need to provide an addition polymerization method of cyclic olefins having a polar functional group and a catalyst composition for producing a cyclic olefin polymer having a polar functional group. In the method, the above-mentioned problems occurring in the related art are avoided, a cyclic olefin polymer having a high molecular weight and the polar functional group is capable of being produced at high yield, and the catalyst residue is not generated.